API changes:
- new field-based serialization API
- removed Updateable
- removed Collection
- removed Collectable._ids and Stop.train_station_name
- added Collectable.id, Collectable.source, Stop.full_name, Stop.uic and Ride.time
- changed module structure for networks and network APIs. Networks are now instances of their API, not \* subclasses.
- removed all old choo APIs
- new simple command line API
- new HTTP API
Added Network:
- VRN (Verkehrsverbund Rhein-Neckar)
Fixes and Improvements:
- various improvements in efa parsing
- refactored code and function names in efa
- flake8 compliant
- added travis